Drinking water cooler

ABSTRACT

A liquid cooling system comprising: a liquid inlet and outlet; one or more liquid reservoirs in fluid communication with the liquid inlet and outlet; an evaporative element in fluid communication with a liquid reservoir; and a fan in flowable communication with a surface of the evaporative element is provided. The liquid cooling system can cool drinking water. The liquid cooling system can be powered by AC power, DC power, solar power or a combination. The liquid cooling system can be used in-line in a hydration system, for example.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to U.S. provisional patent applicationSer. No. 61/181,943, filed May 28, 2009, which is incorporated byreference in its entirety.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

This invention was made with government support under grantM67854-08-C-6511, awarded by the Department of the Navy. The governmenthas certain rights in the invention.

BACKGROUND OF THE INVENTION

Proper hydration is important for general health, as well as forimproving athletic performance. Poor hydration affects multiple bodysystems. Although the importance of hydration is known, it is usuallyless appealing to drink warm liquids as the ambient temperature rises.Insulation has been used to slow warming of liquids in containers, butis ineffective for long periods of time.

A device to cool drinking water that is small and lightweight, coolswater to below ambient temperature, can be retrofitted with existingequipment packs, is low cost, has a hands free operation, is quiet andis compatible with potable water is needed.

SUMMARY OF THE INVENTION

Provided is a liquid cooler that cools liquid by evaporative cooling. Inan aspect of the invention the liquid cooler includes a liquid inlet andoutlet, one or more liquid reservoirs, a porous material (also referredto herein as “evaporative element”) forming one or more surfaces of theliquid reservoir for evaporative cooling and a fan that forces airacross the surface of the evaporative element to enhance the coolingeffect. A housing which surrounds the liquid reservoirs is used in anembodiment to protect the device, as well as provide the air channelsfor air to flow across the surface of the evaporative element. Alsoprovided is a method of cooling water by evaporative cooling using adevice as described herein. As will be apparent from the description andother materials provided herein such as the figures, the evaporativeelement is attached to the reservoir(s) and forms a portion of thereservoir surface and is in fluid contact with at least a portion of thecontents of the reservoir. In an embodiment, the liquid reservoirs arein fluid communication with each other and one reservoir has a liquidinlet and another reservoir has a liquid outlet.

As used herein, “evaporative element” is a porous material attached tothe liquid reservoir and which forms one or more surfaces of the liquidreservoir for evaporative cooling. “Evaporative element” and “porousmaterial” and other forms of the phrases are used interchangeably hereinunless otherwise specified by the context or language.

Some specific aspects and embodiments of the invention are providedhere. In an aspect of the invention, provided is a liquid cooling systemcomprising: a liquid inlet and outlet; one or more liquid reservoirs influid communication with the liquid inlet and outlet; an evaporativeelement in fluid communication with a liquid reservoir; and a fan withairflow in flowable communication with a surface of the evaporativeelement.

In an aspect of the invention, the system further comprises a housingsurrounding the one or more liquid reservoirs. In an aspect of theinvention, there is an exterior housing which holds thereservoirs/evaporative elements, fan, and fan power source (sourcesinclude batteries and/or solar panel(s)) and protects thereservoirs/evaporative elements. In an embodiment this housing alsodefines the airflow channel geometry with the shape of its innersurfaces. In an aspect of the invention, these airflow channels areshaped such that pressure drop through the airflow channels isminimized, which maximizes the airflow provided by the fan.

The housing is preferably made of lightweight material which canwithstand the force of the intended use. The housing is used to protectthe reservoir(s) and provide airflow channels in one embodiment. Thehousing can be machined to provide airflow channels by having oneportion of the housing with more or less thickness to create grooves,for example. In an aspect of the invention, the housing is ruggedized.The term “ruggedized” means the housing is able to withstand a force,impact, or other load that it is expected to undertake during normaloperation or if the unit is dropped or if an object of reasonable sizeis dropped on the unit.

In an embodiment the housing material is a polymer. In an embodiment thehousing is clear or transparent so the evaporative element can be seen,for test and development purposes. In an embodiment the housing is anydesired color or pattern. In an embodiment, the housing provides anddefines the desired airflow channels for the airflow across theevaporative element. In the case of multiple reservoirs, the housingalso defines the airflow channel between the reservoirs. The amount ofairflow to provide the desired cooling is easily determined by one ofordinary skill in the art using the information provided herein as wellas the information known in the art, and depends on such factors such assurface area of the evaporative element, airflow velocity, airtemperature, and desired cooling efficiency.

In an aspect of the invention, the system further comprises a powersource. The power source is one or more selected from the groupconsisting of: one or more DC batteries, one or more solar panels, oneor more rechargeable batteries, an AC power source and combinationsthereof. In an aspect of the invention, a solar panel is used inconjunction with another power source. In an aspect of the invention,the solar panel is used in conjunction with one or more rechargeablebatteries. In an aspect of this embodiment, the solar panel can be usedto recharge a rechargeable battery. This allows the device to functionwhen the solar power is insufficient to completely power the device, ona cloudy day, for example.

The evaporative element is a porous material in fluid or gaseouscommunication with a portion of the liquid reservoir. In an aspect ofthe invention, the porous material is selected from one or more of:expanded polytetrafluoroethylene (ePTFE), porous (e.g., sintered)plastic, ultra high molecular weight polyethylene (UHMWPE), micro-porousceramic membrane, or a multi-layer laminate material made up of one ormore of the above materials. In an aspect of the invention the porousmaterial forms a surface of a liquid reservoir and is attached to aliquid reservoir. The porous material is attached to a surface of theliquid reservoir using any suitable method, such as adhesive, thermalbonding, mechanical attachment, or others providing sufficient adhesionto prevent liquid leakage between the reservoir and porous material. Inan aspect of the invention one side of the porous material is attachedto a side of a liquid reservoir and another side of the porous materialis surrounded by a material which acts to provide structural support,such as a wire mesh, grid or clamp. All layers of the evaporativeelement should be attached to the reservoir or each other to preventleakage. At least one layer is attached to the reservoir. The embodimentof the invention using a wire mesh or grid is useful to preventdeflection or displacement of the evaporative element, for example, ifthe evaporative element itself is not structurally capable of doing so.

In an aspect of the invention, the liquid reservoir contains one or morea baffles or internal ribs positioned to direct the liquid flow throughthe liquid reservoir. This aspect prevents liquid which is warm ascompared to the cooled liquid from flowing directly from the inlet andoutlet and allows sufficient residence time in the device for thedesired cooling. The baffle or internal rib may occupy any suitable areaof the liquid reservoir. In a specific embodiment of this aspect of theinvention, in a generally rectangular liquid reservoir, the baffle ispositioned approximately half way on the height of the reservoir andextends less than the full length of the reservoir. In an embodiment ofthis aspect of the invention, the baffle is an integral part of thereservoir (i.e., the reservoir and baffle are one piece). In anembodiment of this aspect of the invention, the baffle is attached tothe reservoir using any suitable method, such as glue, thermal bonding,or other method known to one of ordinary skill in the art without undueexperimentation.

In an embodiment where there is more than one liquid reservoir, theliquid reservoirs are attached together in any suitable method using anysuitable material. In an aspect of the invention, the liquid reservoirsare attached together using a tube. In an aspect of the invention, theliquid reservoirs are attached together using a flange or other aspectwhich is positioned on each liquid reservoir at an opposite end from theliquid inlet or outlet. This flange or other attachment means can be anysuitable material, such as metal, plastic, polymer, or other materialwhich are suitable for the desired purpose. When there is more than onereservoir in an aspect of the invention, the liquid flow between thereservoirs can be designed to minimize the air present in thereservoirs.

As is known in the art, the reservoir can be any desired shape,including rectangular cuboid, ovoid, cylindrical (including cylindershollowed out axially to create additional evaporative surface area, oneor more of these channels may be hollowed out along the cylinder length,for example), toroidal, tubular or teardrop. As is known in the art,different shapes may be more desired for different applications or maybe more desired from other perspectives, such as cost or ease ofmanufacturing. It is generally advantageous to cooling performance tohave a large evaporative surface area relative to the amount of fluid inthe reservoir, particularly if a quick cooldown is desired. However, ashape with high volume-to-surface area, the extreme example of which isa sphere, will also provide cooling, albeit more slowly than a reservoirwith the same volume and a different shape allowing for greaterevaporative surface area. These aspects are included in the invention.Any shape that provides a high enough surface area to volume to providethe desired cooling of the liquid is suitable. The surface area tovolume determination to determine if a shape is suitable is easilyperformed using the information provided herein and known to the art.

In an aspect of the invention, a reservoir is generally rectangularcuboid in shape. It is understood there are two length×width faces of arectangular cuboid. In an aspect of the invention, the porous materialforms at least a portion of a length×width face of a rectangular cuboidliquid reservoir. In an aspect of the invention, the porous materialforms at least a portion of both length×width faces of a rectangularcuboid liquid reservoir. As is understood, if the porous material formsmore surface area of the reservoir the cooling rate is generallyincreased, providing that sufficient airflow is provided.

In an aspect of the invention, the porous material forms at least 50% ofthe surface area of a reservoir. In an aspect of the invention, theporous material forms up to 100% of the surface area of a reservoir andany percentage thereof. In an aspect of the invention, the porousmaterial forms a percentage of the surface area of a length×width faceof a rectangular reservoir between 10% and 100%. In an aspect of theinvention, the porous material forms less than 50% of the surface areaof a reservoir. In an aspect of the invention, the porous material onone of the length×width face of the rectangular cuboid is different thanthe evaporative element on the other length×width face of therectangular cuboid. In an aspect of the invention, the evaporativeelement on one of the length×width face of the rectangular cuboid is thesame as the evaporative element on the other length×width face of therectangular cuboid. Surface area of the reservoir which does not includeporous material can be enclosed using any other suitable material suchas the same material making up the reservoir, for example. In anembodiment it may be desirable to cover only a portion of the availablesurface area of the reservoir with evaporative element, for variousreasons, such as cost and structural strength. When the term “attachedto” is used in conjunction with the porous material and reservoir, it isintended to indicate the porous material forms a portion of the overallshape of the reservoir. It should be clear that a porous material placedover a solid surface will not function as an evaporative element. In anaspect of the invention, a liquid reservoir can be fabricated as anentire shape, such as a rectangle, and the portion of the shape which isdesired to be evaporative element can be removed, using a laser cutteror knife, for example. In other aspects, a liquid reservoir can befabricated to not include the portion which is intended to beevaporative element. For example, if the liquid reservoir is a generallyrectangle shape where the front surface area is intended to beevaporative element, the rectangle can be fabricated to not include thefront surface area or to include a flange, for example for ease ofpositioning and/or attaching the evaporative element, or the rectanglecan be fabricated with the front surface area and the desired area canthen be removed.

In an aspect of the invention, an evaporative element is a multi-layerlaminate material where the layers may be the same or differentmaterials. In an aspect of the invention, the evaporative element is asingle-layer porous hydrophobic material where the inner surface istreated to create a hydrophilic layer. In an aspect of the invention,when a multiple-layer evaporative element is used, the hydrophobic layeris a membrane. In an aspect of the invention, the inner layer of themulti-layer laminate is hydrophilic. In an aspect of the invention, theinner surface of a single-layer evaporative element or the inner layerof a multi-layer evaporative element is plasma treated to create ahydrophilic surface. Other treatments to create a hydrophilic surfaceare useful, as is known in the art. Naturally-hydrophilic materials arealso useful and do not require a plasma or other treatment to form ahydrophilic surface. It is known in the art that some treatments ofmaterials to create a hydrophilic surface are permanent and othertreatments of materials to create a hydrophilic surface are not. If atreatment is not permanent, or for other reasons, the performance of theevaporative element in particular and the system in general may bereduced over time. In this event, the evaporative element may bereplaced if desired.

As is known in the art, hydrophilic and hydrophobic are relative termsand are not intended to be limiting to a particular polarity orcharacteristic. As is recognized, the hydrophilicity and hydrophobicityof the evaporative element is useful to prevent the passage of liquidfrom one surface of the evaporative element to another, in anembodiment. This aspect is discussed further herein.

In an aspect of the invention, the device is modular or partiallymodular. As used herein, modular means that any element can be removedand replaced with the same or similar element. For example, in anembodiment of the liquid cooler which includes two reservoirs, a modulardevice allows removal and replacement of one or both reservoirs. In anembodiment of a modular device, one or more of the evaporative elementsused on a reservoir may be replaced with the same type of evaporativeelement or a different type of evaporative element, for example. This isuseful in the event of element failure or fouling, for example. Othercomponents and elements of the device are also replaceable. In anembodiment of a modular device, one or more of the reservoirs may bereplaced, for example. The elements or components can clip in to a framefor ease of replacement for example. As is typical for systems forwater, mold and mildew may be a concern and the modularity provides auseful and efficient way to provide a clean system when desired.

As used herein, “device” and “system” are used synonymously unlessotherwise indicated by the language or context.

As is apparent to one of ordinary skill in the art, the device can haveone, two, three or other numbers of reservoirs of varying size and shapeto provide the desired water supply, liquid cooling rate and consumptionamount. The physical and fluid attachments of the reservoirs togetherare made in any suitable manner, as will be appreciated by one ofordinary skill in the art. In an aspect of the invention, the systemcomprises two liquid reservoirs. In an aspect of the invention, thesystem comprises a plurality of liquid reservoirs. In an aspect of theinvention, the system further comprises a gas source in gaseouscommunication with the evaporative element. Although the word “air” istypically used herein to describe the substance that flows over theevaporative element, it is apparent to one of ordinary skill in the artthat other gaseous substances can be used. These other gaseoussubstances are intended to be included in the invention to the sameextent as if they were individually listed. In an aspect of theinvention, the gas is not air. In an example, helium, nitrogen or othergas can be used to create the desired airflow across the evaporativeelement. Generally, any gas with a lower vapor pressure of the liquid tobe cooled than the vapor pressure of the liquid itself within thereservoir is suitable to create cooling. For example, dry air is betterthan moist or humid air for cooling water, warm water is more easilycooled than cool water, dry bottled gases are very effective for coolingwater since they contain less moisture than ambient air, and any ambientairstream, regardless of humidity, is effective at cooling processliquids whose vapors are not present in the atmosphere such as solvents.All of these aspects are included in the invention.

In an aspect of the invention, the system further comprises a switch inelectrical communication with the fan. In an aspect of the invention,the switch is operated by the user to allow cooling of the water upondemand. In an embodiment of the invention the switch is located on ornear the housing. In an embodiment of the invention the switch islocated remotely from the device, so the user can easily access theswitch while walking, for example. In an embodiment of the invention theswitch is wireless. In an embodiment of the invention the switch iselectrically connected to the device using a wire or other electricalconnection.

In an aspect of the invention, the system further comprises airflowchannels on one or both sides of the reservoir and/or evaporativeelements. These airflow channels may be provided by a housing, in oneembodiment. The airflow channels may also be fabricated into thereservoir and/or evaporative elements. In an aspect of the invention,the airflow channels are sized and scaled to meet water/liquidcooling/consumption requirements. In an aspect of the invention, thereis a screen or filter positioned adjacent to an evaporative element toprevent fouling of the evaporative element. This is particularly usefulin an environment where there is no housing.

As is apparent to one of ordinary skill in the art, the powerrequirements of the fan can vary depending on the desired airflow andother considerations such as size of the device. In an aspect of theinvention, the fan draws between 0.25-1 W of power and all ranges andvalues therein. Of course, as will be apparent to one of ordinary skillin the art, if the device is scaled to a larger size, a larger fan willbe required to meet the airflow requirements. In this case, the fan maydraw more than 1 W power.

As will be apparent to one of ordinary skill in the art from thedisclosure herein, the apparatus and method can be used to cool anysuitable liquid. In an aspect of the invention, the liquid is water. Inan aspect of the invention, the liquid is drinking water. In an aspectof the invention, the liquid is suitable for human or animal consumptionand the surfaces of the cooling system which contact the liquid areapproved for potable water systems. The liquid cooled using the systemand methods described here can also be a fluid used in industry. In anembodiment, the liquid is an organic solvent. In an embodiment, theliquid is an inorganic solvent.

In an aspect of the invention, the system is inserted into the liquidsupply line of a hydration system between the bladder and mouth piece.This insertion can be performed by merely cutting the liquid supply lineand inserting a suitable coupling piece, or in other ways as will beappreciated by one of ordinary skill in the art.

The performance of the system and methods provided can vary depending onthe desired use and components used. In an aspect of the invention, inoperation, the liquid is cooled by at least 8° F. in 5 minutes. In anaspect of the invention, in operation, the liquid is cooled by at least10° F. in 5 minutes. In an aspect of the invention, in operation, theliquid is cooled by at least 15° F. in 5 minutes. In an aspect of theinvention, in operation, the liquid is cooled by at least 15° F. in 10minutes. In an aspect of the invention, in operation, the liquid iscooled by at least 20° F. in 10 minutes. In an aspect of the invention,in operation, the liquid is cooled by at least 36° F. in 5 minutes. Inan aspect of the invention, in operation, the liquid is cooled by atleast 36° F. in 10 minutes. Other temperature reductions in varioustimes are included in the invention.

Also provided is a liquid cooling system comprising: one or more liquidreservoirs having a liquid inlet and a liquid outlet; and one or moreevaporative element(s) in liquid communication with the one or moreliquid reservoirs, wherein gas passes over the evaporative element(s)and cools liquid in a reservoir. In this embodiment, there is no fan orpower supply, and the airflow which augments evaporation is providedeither by the system being in motion or by ambient airflow/breezes. Inthis embodiment, there may be a housing which protects the evaporativeelements and defines the airflow channels and is designed to minimizeblockage of airflow over the evaporative element(s). This configurationcan be used by bicyclists, for example. In another embodiment, the flowaugmenting cooling can be provided by bottled gas(es). Thisconfiguration can be used in laboratory or manufacturing settings, forexample.

Also provided is a method to cool liquids comprising providing: a liquidcooling system comprising: a liquid inlet and outlet; one or more liquidreservoirs; and an evaporative element; and providing airflow over theevaporative element.

Also provided is a method of cooling liquid comprising: providing aliquid cooling system comprising: a liquid inlet and outlet, one or moreliquid reservoirs, a porous evaporative element attached to one or moresurfaces of the liquid reservoir for evaporative cooling, and a fan thatforces air across the surface of the evaporative element; providingliquid in the liquid reservoir; activating the fan; and allowingevaporation to occur, whereby liquid in the liquid reservoir is cooled.The system configurations described elsewhere are useful in the methodsdescribed herein. Any aspect of the invention which is described as adevice can be used in a method for cooling water.

In an aspect of the invention, the method comprises drawing the liquidthrough the reservoir at a constant rate. A constant rate may also bethought of as a continuous flow for a certain period of time. Thisembodiment is useful for a larger scale operation where there issufficient cooling provided so that the liquid withdrawn from the deviceis cooler than the liquid provided to the device, for example. In anaspect of the invention, the method comprises drawing the liquid throughthe reservoir at a variable rate, determined by a user withdrawing theliquid or an external mechanical system. A variable rate may also bethought of as a discrete volume flow. In the constant-flow embodiment,the flow rate may be low relative to the volume of liquid being cooledso that desired cooling can occur before the liquid exits the reservoir.An example of a variable-reservoir-flow embodiment where cooling of aconstant flow of liquid can take place is a large community water sourcewhere the cooled exit flow is used to fill water bottles. In thisembodiment, the flow rate during bottle filling is the maximum flowrate, and the inlet water temperature is elevated relative to apreferred temperature for consumption (e.g., ambient temperature in ahot environment). The flow rate drops to zero between bottle filling,during which time the reservoir water in this embodiment is cooled andheld at or near the ambient wet-bulb temperature through evaporativecooling. An embodiment with purely variable flow is a “batch-cooling”embodiment where one or multiple reservoirs collectively comprise abatch of water to be cooled via evaporation of a small portion of thewater within the reservoirs. Once this batch of water is cooled to thedesired temperature, it is consumed and replaced with a new batch ofwarm water which is then cooled, and so on. The batch size can be scaledto fit the desired application. All variations on the constant andvariable flow rate embodiments are included here.

Also provided is a device comprising: one or more porous liquidreservoirs; and a battery-powered fan; wherein the device cools theliquid in the liquid reservoirs by evaporative cooling of the fan orflow over the porous liquid reservoirs.

Any device described here can include an optional solar panel withaccompanying wiring and physical connections to the device as will beknown to one of ordinary skill in the art. The solar panel can be usedto power the device alone or in conjunction with one or more batteriesor AC power sources. In an embodiment, the solar panel is used torecharge rechargeable batteries.

The device can be fabricated to any desired pressure specifications. Inan embodiment, the device operates at an internal pressure of at least 1psig without leaking water and a negative pressure of at least 1 psigwithout leaking air into the liquid reservoir. In an embodiment, thedevice operates at an internal pressure of at least 2 psig withoutleaking water and a negative pressure of at least 2 psig without leakingair into the liquid reservoir. In an embodiment, the device operates atan internal pressure of less than 2 psig without leaking water and anegative pressure of less than 2 psig without leaking air into theliquid reservoir. Any individual value or range within the rangessupplied are intended to be included to the same extent as if they wereindividually listed.

In an aspect of the invention, a portion of the liquid reservoirscomprise a porous material or layered porous materials such that theevaporative cooling effect provides desired cooling performance. In anaspect of the invention, the porous material or layered porous materialcomprises one or more of: expanded polytetrafluoroethylene (ePTFE),sintered porous plastic, and metallic and non-metallic screen to provideneeded structural support. In an aspect of the invention, the deviceoperates for over 12 hours with 4 CR123A batteries. In an aspect of theinvention, the device operates for >12 hours with ≦4 CR123 A batteriesor a solar panel. In an aspect of the invention, the device cools asmall volume (2-3 oz) of water, initially at 120° F. in 120° F. airtemperature/15% humidity, to below body temperature in less than 10minutes.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 provides exemplary system components of an embodiment of theinvention.

FIG. 2 illustrates a specific embodiment of how the system can bepositioned inline with a hydration pack.

FIG. 3 shows an exemplary embodiment shown integrated with a hydrationpack.

FIG. 4 shows an exemplary DWC evaporative cooling process.

FIG. 5A shows a reservoir example with exemplary dimensions. FIG. 5Bshows an exemplary evaporative element having two materials.

FIG. 6 shows exemplary reservoirs: Tetratex laminate with mesh screen(top) and Tetratex only (bottom).

FIG. 7A-E show exemplary systems with two reservoirs.

FIG. 8A, 8B and 8C provide examples of cooling performance.

FIG. 9 shows potential steady-state cooling performance in variousenvironments based on thermal modeling and lab testing.

DETAILED DESCRIPTION OF THE INVENTION

In general, the terms and phrases used herein have their art-recognizedmeaning, which can be found by reference to standard texts, journalreferences and contexts known to those skilled in the art. As to theembodiments of the invention, it is understood that any embodimenthaving a combination of components which is not able to be made is notincluded in the invention. Although Applicant does not wish to be boundby theory, the description herein is provided to aid in understanding ofthe invention. The following description is provided to illustratespecific embodiments of the invention. It is understood that all aspectsof the invention which are described using a specific embodiment orembodiments referred to in the alternative (one or more liquidreservoirs, for example) are applicable to other embodiments and areintended to be disclosed herein to the same extent as if they werespecifically listed.

As will be appreciated, the drinking water cooler can have a variety ofconfigurations. FIG. 1 illustrates one configuration of the providedsystem with two reservoirs and a cap with air flow slots and a tetheredswitch. FIGS. 2 and 3 show one example of a use of the invention wherethe drinking water cooler is incorporated into a hydration pack. Theinvention is useful for military applications, as well as in otheroccupations that require wearing restrictive industrial garments (suchas fire fighters, law enforcement, hazardous waste cleanup) andrecreational users.

In an aspect of the invention, the apparatus size is such that willprovide an adequate amount of cooled water but will take up as small anamount of space as possible. In certain uses, the device is as quiet aspossible. In an embodiment, the device weighs as little as possible. Inan embodiment, the device costs as little as is feasible to manufacture.As will be appreciated, there is a tradeoff between the size, weight,noise, volume and power needed with the cost and reliability of thedevice. One of ordinary skill in the art will understand the tradeoffsrequired for the desired purpose. The liquid cooler can be any suitablesize to provide the desired amount of cooled liquid. If a greater amountof cooled liquid is required, the system can be scaled up appropriately.

In an embodiment, exemplary dimensions of the system are approximately(L×W×H): 14.7×6.9×4.0 cm; system volume of 299 cm³ (18 in³); input powerof 0.5 W @ 12 VDC (continuous operation); noise 22 dBA (normallydetermined by the specifications of the fan); and dry weight 8.2 oz. Itis appreciated by one of ordinary skill in the art that the provideddimensions and specifications are exemplary and may change. All changesare intended to be incorporated herein.

Testing of Fan Power on Lifetime and Cooling Airflow

In an exemplary system, the input power is ≦0.5 W, ≦22 dBA, totalreservoir volume is approximately 2.3 oz. In testing of an exemplaryembodiment, it was shown that a 0.5 W fan was statistically as effectiveas a 1.0 W fan at providing evaporative cooling airflow. The inherentreduction in airflow provided by a lower power fan did not negativelyaffect unit performance. In a further test, a reduction in fan inputpower to 0.25 W did not detrimentally affect performance. These resultsshow a doubling of DWC operation time if four batteries are used, or areduction in number of batteries used (i.e., from four to two) with nonet effect on operation time. In an aspect of the invention atwo-battery system creates a 6-V power source for a fan designed for a5-V power source, which may shorten the fan lifetime. In addition,depending on the components, the fan noise is reduced to as low as 13dBA from 22 dBA by use of a 0.25 W fan.

In an aspect of the invention the input power is a 1 W fan. In an aspectof the invention the input power is a <1 W fan. In an aspect of theinvention the input power is a 0.5 W fan. In an aspect of the inventionthe input power is a <0.5 W fan. In an aspect of the invention the inputpower is a 0.25 W fan.

In an aspect of the invention a solar panel is used as an alternative orsupplemental power source. The solar panel is designed so that the solarpanel will re-charge spent or degraded rechargeable batteries. Therechargeable batteries may be used as backup power in cloudy, shaded, ornighttime conditions.

As known in the art, the specifications of the system and componentsthereof can vary, depending on many factors, including the overalldesired size and/or weight of the system, the amount of cooling desired,the cost of the system, the specifications of the “off-the-shelf”components, manufacturing requirements, and other considerations whichare well-understood by one of ordinary skill in the art. As known in theart, materials used for the components such as switch components,batteries, tubing, housing materials, fan, methods of attachingcomponents together and reservoir frame materials may vary, depending onthe factors discussed herein and other factors known in the art ofdesigning systems. All such modifications are intended to be includedherein.

Although the invention is described in detail using the term “drinkingwater” it is understood that other liquids may be cooled using theinvention. As known in the art, the DWC system can be used to cool mostliquids, including water, sports drinks, alcoholic beverages, coffee,tea, and any other desired beverage. These embodiments are wellunderstood by one of ordinary skill in the art using the description andteachings described herein without undue experimentation, and areintended to be included herein.

As is apparent to one of ordinary skill in the art, some liquids willdamage the reservoir materials before sufficient cooling of some extremeexample liquids will occur. For example, an evaporative cooler thatcools liquid tungsten is impossible to make since all potentialreservoir materials would melt/burn/evaporate before the tungsten melts.Materials that become fluids at extremely high temperatures aregenerally not feasible for cooling with this unit.

A class of liquids that can be cooled using the methods and apparatusdescribed herein are process liquids such as methyl ethyl ketone (MEK)or acetone. In operation, it is desired that the vapors from anevaporative cooler cooling such liquids be contained as necessary forsafety reasons such as vapor flammability or toxicity. In thisembodiment, it is likely that the air or other gas used to enhanceevaporation will come from a bottled or otherwise contained source. Themethods and apparatus described herein are a viable way to providecooling of these industrial fluids if it is needed in a manufacturingprocess or for other uses.

Operation of DWC

In one example of operation, the DWC is inserted in a hydration packwater line (such as a Camelbak or similar system) at any suitablelocation between the hydration bladder and the mouth piece. Thereservoir of the DWC is filled with the desired liquid (in oneembodiment, this filling occurs when the user withdraws liquid from thereservoir which is replaced by water remaining in the hydration pack).For this exemplary description, water is used as the liquid, althoughthe principles of operation will be the same for any other liquid used.A small portion of the stored water in the reservoir evaporates throughthe evaporative element that is in contact with the reservoir or aportion thereof. This evaporation cools the remaining water in thereservoir. The cooled water is consumed and replaced with water from thehydration pack, which is then cooled, and so on representing abatch-cooling process. In an embodiment, air is forced across theevaporative element to increase the evaporative cooling. This air flowcan be produced using a fan or other device which increases air flow.

In operation, the reservoir volume remains near-constant during cooling(assuming the DWC water pressure remains constant). Water evaporatedfrom the reservoir during cooling is replaced by water from thehydration pack (or by water from the tubing connecting the hydrationpack and the DWC). Since this is a small amount of water compared to thereservoir volume (because of water's high heat of vaporization), thisdoes not have a significant detrimental affect on cooling performance.In a system cooling a fluid with a low heat of vaporization, thereduction in temperature, or the time needed to reach a desiredtemperature, may be detrimentally affected since a larger proportion ofliquid must evaporate to provide desired cooling.

In an embodiment, exemplary parameters of the system are based on thefollowing consumption profile: water consumption takes place in sets ofsips, three to five sips taken with 1-2 seconds between sips. In anembodiment, the reservoir capacity (combined) is 2.3 oz. In thisembodiment, a six-minute consumption (cooldown) interval maintains anoverall consumption rate of approximately 23 oz/hour.

Other parameters may be used, such as larger or smaller reservoircapacities, different reservoir geometries, different numbers ofreservoirs, and larger or smaller time interval for desired coolingeffect.

DWC Evaporation

Cooling is provided by the evaporation of water. The heat ofvaporization of a small portion of water in the reservoir is used tocool the remaining drinking water within the reservoir. This is the sameprocess as sweating that cools the body. The proportion of reservoirliquid needed to evaporative in order to cool the liquid remaining inthe reservoir depends on the liquid's heat of vaporization and heatcapacity. For example, it is feasible to cool a reservoir of water by36° F. by evaporating as little as 3.5% of the water therein due towater's relatively high heat of vaporization. The refrigerant R134arequires over 15% of the liquid to evaporate to produce the same effect.A device having any amount of liquid evaporation is included in theinvention as long as the liquid is not 100% evaporated before it reachesthe liquid output.

In an embodiment, evaporation can be enhanced via forcing air around thereservoirs with the use of a fan or other method known in the art. Thefan can be powered by one or any combination of: batteries, a solarpanel, a wall outlet, or other suitable source of power.

Evaporative Element

The evaporative element can be made of a number of materials. Theinternal surface of the evaporative element in contact with the water inthe reservoir must be a hydrophilic porous material that absorbs waterlike a blotter and prevents passage of air when pressure in reservoir isbelow that on air-side of the evaporative element, as may occur due tosuction created to draw the liquid to the user during consumption. Theexternal evaporative surface in contact with air must be a material thatallows passage of water vapor (i.e., evaporation), but prevents thepassage of liquid water and remains dry at the surface (hydrophobic).These requirements can be achieved by a single porous hydrophobicmaterial having a conventional surface treatment (such as plasma orcorona discharge treatment, chemical etching, or an applied coating) tomake one surface (and a portion of the total material thickness)hydrophilic. Alternatively, a multi-layer laminate may be used. Thelayers in the multi-layer laminate may be the same or different, and maybe comprised of one or more of the materials listed below or othersuitable materials. Some specific materials useful for the evaporativeelement include: expanded polytetrafluoroethylene (ePTFE), porous (e.g.,sintered) plastic including ultra high molecular weight polyethylene(UHMWPE), or micro-porous ceramic membrane and other suitable materials.FIG. 4 shows the evaporative cooling process of the systems of theinvention. An expanded view of an exemplary reservoir with theevaporative elements is shown in FIG. 5.

In an embodiment, the reservoir assembly (including evaporativeelement(s)) can easily be disconnected from the water inlet and outletlines, and the housing can be opened so that the reservoir assembly canbe removed and replaced with a new reservoir assembly if needed due toevaporative element degradation and/or soiling. This represents amodular reservoir assembly design.

The reservoir(s) may be designed such that the presence of air bubblesis minimized during the initial filling of the reservoir(s), and suchthat consumption of water within the system is conducive to purgingexisting air bubbles within the reservoir(s).

The reservoirs may include baffles to direct the flow of water withinthe reservoirs during consumption in a way that mitigates potentialmixing of warm water from the hydration system with cooled water beforeall or a significant majority of the cooled water is consumed.

In an embodiment comprising a multiple-reservoir system, the reservoirsmay be connected with a section of tubing. This tubing section may runbetween barb or other suitable types of fitting integrated into theindividual reservoirs. Other suitable connection methods known in theart, including but not limited to quick-connect fittings or plumbingfittings, may be used if desired.

As is known in the art, there are different suitable methods ofattaching the laminate layers both to each other and to the reservoirframe. The layers can be attached to each other either at the outsideedges via adhesive(s), thermal bonding, ultrasonic welding, stitching,and/or other means, or over some or all of their surfaces in contactwith one another by adhesive(s), thermal bonding, ultrasonic welding,stitching, and/or other means. The attachment method should notdetrimentally affect the transport of liquid through the hydrophiliclayer or the transport of vapor though the hydrophobic layer to thepoint where cooling performance is compromised. The evaporative elementcan be attached to the reservoir frame by adhesive(s), thermal bonding,ultrasonic welding, stitching, and/or other means. In the case of adrinking water (or other beverage) cooling system, substances in contactwith the water/beverage (i.e., reservoir, evaporative element, and anyadhesives/other bonding agents) must be approved for use with potablewater systems. These methods are known in the art and are selected byconsiderations such as the desired use and the materials available andother considerations such as cost and performance.

In an embodiment, the evaporative element has the followingcharacteristics:

-   -   High evaporative cooling effectiveness    -   No water leakage at 24-in positive water pressure    -   No air leakage at 24-in negative water pressure; capillary force        of the hydrophilic layer must overcome suction while user drinks    -   Structurally sturdy, i.e., does not deflect significantly inward        or outward with negative and positive water pressures,        respectively, thereby avoiding reservoir water volume reduction        or airflow channel restriction    -   Laminated layers do not detach (in the case of a multiple-layer        evaporative element)    -   Tolerates dust-laden environments    -   Easily cleaned    -   Non-toxic/approved for use in potable water systems (if        applicable based on liquid)    -   Bacteria/mold/mildew-resistant    -   Low cost

As is known in the art, the characteristics above may vary, depending onthe desired application and other factors known in the art. For example,water or air leakage may occur, although the amount of water of airleakage is desired to be minimized. In addition, the specified limit forwater or air leakage may be higher or lower, depending on variousaspects of the system as described herein and known to the art.

Performance

An exemplary DWC system was fabricated and operated to demonstrate thecooling performance at simulated hot desert conditions. For initialtesting, reservoirs were fabricated by epoxy bonding porous ePTFE toreservoir frames both with and without sintered porous plastic.

For the laminate assembly: 25-mil thick porous UHMWPE sintered plastic(DeWAL Industries #492P), Tetratex® (ePTFE/polypropylene matlaminate-Donaldson Company product # 6502), and 0.25×0.25″ stainlesssteel wire mesh (0.028″ diameter) were layered and only bonded at theperimeter of the reservoir housing. This layered assembly was bonded toboth sides of a plastic reservoir frame such that it would contain waterwithout leakage. Pressure testing confirmed no water leakage at 24 in ofwater and no air leakage at up to 15 in negative water pressure withinthe reservoir. For one example Tetratex (product #6502) was bonded aloneto both sides of the reservoir for performance comparison testing. Thismaterial alone provides resistance to water leakage, but no resistanceto air leakage. Tetratex product #6502 is an ePTFE membrane laminated toa thin, open polypropylene scrim. These two reservoir assemblies areshown in FIG. 6. The reservoirs are shown contained in the clear examplehousing for use and testing in FIG. 7.

In an embodiment of a laminate material, Tetratex 6502 is used with a40-mil (0.040-in) thick porous plastic plasma treated forhydrophilicity. This porous plastic has a slightly smaller pore sizewhich allows for air intrusion prevention to a reservoir vacuum level ofat least 31 inches of water when it is saturated.

FIG. 9 shows theoretical steady-state cooling performance in variousenvironments.

The example system also contains the cooling fan, batteries, and switchneeded for operating the cooler. Two different fan power levels wereused for the tests: ½ watt and 1 watt. Both fans are 35×35×10 mmgenerally used for electronics cooling. For the example system, SUNONfan models GM1235PFV1-8 (0.5 W) and GM1235PFV2-8 (1.0 W) were used. FourCR123A batteries provide the nominal 12-V fan power. As known in theart, these components and their specifications may change depending onthe availability, size and cost of the items, among other factorsrecognized and known in the art.

Cooling performance with respect to time for the laminate reservoirdescribed above (but without the wire mesh) is shown in FIG. 8A using a0.5-W fan. Water contained in the reservoir cooled by 37.2° F. in tenminutes when operated in a 120° F., 5% relative humidity environment.The test was performed in the lab with an environmental chamber.

FIG. 8B shows cooling performance with respect to time for the laminatereservoir described above (but without the wire mesh) using a 0.5 W fan.Water contained in the reservoir cooled by 29.9° F. in ten minutes whenoperated in a 120° F., 15% relative humidity environment. The test wasalso performed in the lab in the same environmental chamber. It shouldbe noted that in 120° F. ambient conditions, the relative humidity isgenerally between 5 and 15%, which corresponds to 30° F. and 60° F. dewpoint temperatures, respectively.

In lab testing in the same environmental chamber, water contained in theTetratex only reservoir cooled by 23.4 and 30.9° F. at 5 and 10 minutesrespectively at 120° F./15% relative humidity conditions indicating thatthe performance penalty associated with the 25-mil thick porous plasticaddition was small.

FIG. 8C shows cooling performance with the tests performed in adifferent environmental chamber under different conditions.

The degree of cooling described in the description herein and in theclaims are necessarily affected by the ambient conditions, includingtemperature and humidity, as known by one of ordinary skill in the artand illustrated in FIG. 8.

All such variables are contemplated and all degrees of performance areintended to be included in the invention.

REFERENCES

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It must be noted that as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural reference unless thecontext clearly dictates otherwise. Thus, for example, reference to “areservoir” includes a plurality of such reservoirs and equivalentsthereof known to those skilled in the art, and so forth. As well, theterms “a” (or “an”), “one or more” and “at least one” can be usedinterchangeably herein. It is also to be noted that the terms“comprising”, “including”, and “having” can be used interchangeably. Theexpression “of any of claims XX-YY” (wherein XX and YY refer to claimnumbers) is intended to provide a multiple dependent claim in thealternative form, and in some embodiments is interchangeable with theexpression “as in any one of claims XX-YY.”

Unless defined otherwise, all technical and scientific terms used hereinhave the same meanings as commonly understood by one of ordinary skillin the art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can be used inthe practice or testing of the invention, the preferred methods andmaterials are now described. Nothing herein is to be construed as anadmission that the invention is not entitled to antedate such disclosureby virtue of prior invention.

STATEMENTS REGARDING INCORPORATION BY REFERENCE AND VARIATIONS

All references throughout this application, for example patent documentsincluding issued or granted patents or equivalents; patent applicationpublications; unpublished patent applications; and non-patent literaturedocuments or other source material; are hereby incorporated by referenceherein in their entireties, as though individually incorporated byreference, to the extent each reference is at least partially notinconsistent with the disclosure in this application (for example, areference that is partially inconsistent is incorporated by referenceexcept for the partially inconsistent portion of the reference). Inaddition, any aspect described herein is intended to be described tosuch an extent so that it may be included or excluded from the claims.

Where the terms “comprise”, “comprises”, “comprised”, or “comprising”are used herein, they are to be interpreted as specifying the presenceof the stated features, integers, steps, or components referred to, butnot to preclude the presence or addition of one or more other feature,integer, step, component, or group thereof. Separate embodiments of theinvention are also intended to be encompassed wherein the terms“comprising” or “comprise(s)” or “comprised” are optionally replacedwith the terms, analogous in grammar, e.g.; “consisting/consist(s)” or“consisting essentially of/consist(s) essentially of” to therebydescribe further embodiments that are not necessarily coextensive. Forclarification, as used herein “comprising” is synonymous with “having,”“including,” “containing,” or “characterized by,” and is inclusive oropen-ended and does not exclude additional, unrecited elements or methodsteps. As used herein, “consisting of” excludes any element, step,component, or ingredient not specified in the claim element. As usedherein, “consisting essentially of” does not exclude materials or stepsthat do not materially affect the basic and novel characteristics of theclaim (e.g., not affecting an active ingredient). In each instanceherein any of the terms “comprising”, “consisting essentially of” and“consisting of” may be replaced with either of the other two terms. Theinvention illustratively described herein suitably may be practiced inthe absence of any element or elements, limitation or limitations whichis not specifically disclosed herein.

The invention has been described with reference to various specific andpreferred embodiments and techniques. However, it should be understoodthat many variations and modifications may be made while remainingwithin the spirit and scope of the invention. It will be appreciated byone of ordinary skill in the art that methods, devices, device elements,materials, optional features, procedures and techniques other than thosespecifically described herein can be applied to the practice of theinvention as broadly disclosed herein without resort to undueexperimentation. All art-known functional equivalents of methods,devices, device elements, materials, procedures and techniques describedherein; and portions thereof; are intended to be encompassed by thisinvention. Whenever a range is disclosed, all subranges and individualvalues are intended to be encompassed. This invention is not to belimited by the embodiments disclosed, including any shown in thedrawings or exemplified in the specification, which are given by way ofexample or illustration and not of limitation.

1. A liquid cooling system comprising: a liquid inlet and outlet; one ormore liquid reservoirs in fluid communication with the liquid inlet andoutlet; an evaporative element in fluid communication with a liquidreservoir; and a fan with air flow in flowable communication with asurface of the evaporative element.
 2. The system of claim 1, furthercomprising a power source.
 3. The system of claim 2, wherein the powersource is one or more selected from the group consisting of: a DCbattery, a solar panel, a rechargeable battery and an AC power source.4. The system of claim 1, wherein an evaporative element is a porousmaterial in fluid or gaseous communication with a portion of the liquidreservoir.
 5. The system of claim 4, wherein the porous material isselected from one or more of: expanded polytetrafluoroethylene (ePTFE),porous (e.g., sintered) plastic, ultra high molecular weightpolyethylene (UHMWPE), multi-layer laminate material and micro-porousceramic membrane.
 6. The system of claim 5, wherein the porous materialforms a surface of a liquid reservoir.
 7. The system of claim 1, whereina reservoir is generally rectangular cuboid, ovoid, cylindrical,hollowed out cylindrical, toroidal, tubular or teardrop in shape. 8.(canceled)
 9. The system of claim 4, wherein the porous material formsat least a portion of a length×width face of a rectangular cuboid liquidreservoir.
 10. The system of claim 9, wherein the porous material formsat least a portion of both length×width faces of a rectangular cuboidliquid reservoir.
 11. The system of claim 4, wherein the porous materialforms at least 50% of the surface area of a reservoir.
 12. The system ofclaim 4, wherein the porous material forms less than 50% of the surfacearea of a reservoir.
 13. The system of claim 9, wherein the porousmaterial on one of the length×width face of the rectangular cuboid isdifferent than the evaporative element on the other length×width face ofthe rectangular cuboid.
 14. The system of claim 9, wherein theevaporative element on one of the length×width face of the rectangularcuboid is the same as the evaporative element on the other length×widthface of the rectangular cuboid.
 15. The system of claim 1, wherein anevaporative element is a multi-layer laminate material where the layersmay be the same or different materials.
 16. (canceled)
 17. The system ofclaim 1, wherein the evaporative element is a single-layer poroushydrophobic material having the inner surface treated to create ahydrophilic layer.
 18. The system of claim 15, wherein the inner layerof the multi-layer laminate is hydrophilic.
 19. The system of claim 18,wherein the inner surface of a single-layer evaporative element or theinner layer of a multi-layer evaporative element is plasma treated tocreate a hydrophilic surface.
 20. (canceled)
 21. The system of claim 1,wherein the system comprises a plurality of liquid reservoirs.
 22. Thesystem of claim 1, further comprising a gas source in gaseouscommunication with the evaporative element.
 23. (canceled)
 24. Thesystem of claim 1, further comprising a switch in electricalcommunication with the fan.
 25. The system of claim 1, furthercomprising a housing surrounding the one or more liquid reservoirs. 26.The system of claim 1, further comprising airflow channels positioned onan evaporative element.
 27. The system of claim 25, wherein the housingprovides airflow channels for the airflow.
 28. The system of claim 1,further comprising a screen or filter positioned adjacent to anevaporative element.
 29. The system of claim 1, wherein the fan drawsbetween 0.25-1 W of power.
 30. The system of claim 1, wherein the liquidis water. 31-32. (canceled)
 33. The system of claim 1, wherein thehousing is ruggedized.
 34. The system of claim 1, wherein the system isinserted into the liquid supply line of a hydration system between thebladder and mouth piece.
 35. The system of claim 1, wherein inoperation, the liquid is cooled by at least 8° F. in 5 minutes.
 36. Thesystem of claim 1, wherein in operation, the liquid is cooled by atleast 10° F. in 5 minutes.
 37. The system of claim 1, wherein inoperation, the liquid is cooled by at least 15° F. in 5 minutes.
 38. Thesystem of claim 1, wherein in operation, the liquid is cooled by atleast 15° F. in 10 minutes.
 39. The system of claim 1, wherein inoperation, the liquid is cooled by at least 20° F. in 10 minutes. 40.The system of claim 1, wherein in operation, the liquid is cooled by atleast 36° F. in 5 minutes.
 41. The system of claim 1, wherein inoperation, the liquid is cooled by at least 36° F. in 10 minutes. 42.The system of claim 1, wherein in operation, less than 10% of thereservoir volume is evaporated to produce the desired cooling effect.43-44. (canceled)
 45. A method of cooling liquid comprising: providing aliquid cooling system comprising: a liquid inlet and outlet, one or moreliquid reservoirs, a porous evaporative element attached to one or moresurfaces of the liquid reservoir for evaporative cooling, and a fan thatforces air across the surface of the evaporative element; providingliquid in the liquid reservoir; activating the fan; and allowingevaporation to occur, whereby liquid in the liquid reservoir is cooled.46-74. (canceled)
 75. A device comprising: one or more porous liquidreservoirs; and a battery-powered fan; wherein the device cools theliquid in the liquid reservoirs by evaporative cooling of the fan orflow over the porous liquid reservoirs.
 76. (canceled)
 77. The device ofclaim 75, which operates at an internal pressure of at least 1 psigwithout leaking water and an negative pressure of at least 1 psigwithout leaking air into the porous liquid reservoir.
 78. The device ofclaim 75, wherein at least a portion of the porous liquid reservoirscomprise a porous material or layered porous materials such that theevaporative cooling effect provides desired cooling performance.
 79. Thedevice of claim 78, wherein the porous material or layered porousmaterial comprises one or more of: expanded polytetrafluoroethylene(ePTFE), sintered porous plastic, and metallic and non-metallic screento provide needed structural support.
 80. (canceled)
 81. The device ofclaim 75 wherein the porous liquid reservoir comprises a single-layerporous hydrophobic material having the inner surface treated to create ahydrophilic layer.
 82. The device of claim 79 wherein the porous liquidreservoir comprises a multi-layer porous hydrophobic material having theinner layer of the multi-layer laminate treated to create a hydrophiliclayer.
 83. The device of claim 75 wherein the inner hydrophilic surfaceof a single-layer evaporative element or the inner hydrophilic layer ofa multi-layer evaporative element is plasma treated to provide ahydrophilic surface. 84-85. (canceled)
 86. The device in claim 75 whichcools a small volume (2-3 oz) of water, initially at 120° F. in 120° F.air temperature/15% humidity, to below body temperature in less than 10minutes.
 87. The device in claim 75 which is scalable to cool the volumedesired.